The micro fabrication technology enables the micro-electro-mechanical system (MEMS) to integrate mechanical elements, sensing elements, actuators and electronic elements on a common silicon substrate. In recent years, MEMS accelerometers are grown more than hundred-fold in the communication market, such as cell phones. Many technologies on MEMS accelerometer structure are developed.
U.S. Patent Publication No. 2007/0114623 discloses a method for manufacturing a micro-electro-mechanical component, and a micro-electro-mechanical component. As shown in FIG. 1, the disclosed technology uses a cover part 120 with vertical electroplated conductive areas 110 for the vertical integration system module package of preliminary sealing mount package of sensor chip and application specific IC (ASIC). This package is to assemble preliminary sealing mount packaged MEMS sensor chip 130 and ASIC 140 through anodic bonding and flip-flop bonding processes respectively, such as using arranged flip-flop bonding bumps 161-163 and bump connectors 169-170, to the opposite sides of cover part 120. Between ASIC 140 and MEMS sensor chip 130, the serial connection of the system routing is achieved through the conductive layout and vertical electroplated conductive areas 110 on both sides of cover part 120. The flip-flop bonding process of ASIC 140 and cover part 120 is conducted in an individual chip bonding manner.
U.S. Pat. No. 6,750,521 discloses a surface mount package for MEMS components. As shown in FIG. 2, capped chip 216 is bonded to device chip 212 through seal ring 232 using solder bonding. Capped chip 216 includes a lower surface 222 facing device chip 212, an opposite upper surface 224 and electronic connection elements between the two surfaces. These electronic connection elements electrically communicate with runner 226 above device chip 212. Runner 226 is electrically connected to a micromachine 214 to provide a signal path from micromachine 214 to the exterior of device chip 214.
Capped chip 216 further includes a bond pad 220 to communicate electrically with electronic connection elements. Through solder connection 230 formed by the reflow of solder bump 234 above bond pad 220, capped chip 216 can be packaged to a circuit board including device chip 212 and micromachine 214 in a surface mount package manner. Micromachine 214 above device chip 212 is included inside a cavity 218; hence, the surface mount package reserves the sensing cavity space in capped chip 216.
U.S. Pat. No. 7,275,424 discloses a wafer level capped sensor. As shown in FIG. 3, sensor 310 comprises a die 314, a cap wafer 312, and a conductive pathway 318. Die 314 includes a working portion 330. Cap wafer 312 and die 314 are coupled to a part of working portion 330. Flip-flop contact balls 342 are formed on metal contacts 340, and conductive pathway 318 passes through cap wafer 312 and extends to working portion 330 to provide an electrical interface to working portion 330. Cap wafer 312 includes a cavity 326 to form an internal chamber to protect working portion 330 of die 314. Hence, sensing cavity chamber of sensor 310 is reserved in cap wafer 312. Gap 334 between cap wafer 312 and die 314 may be filled with polymer and seal glass 352.